This invention is in the field of non-invasive spectral analysis of analytes in tissues and relates more particularly to a device which may be used with a non-invasive monitoring system used for determining concentrations of various blood components.
Non-invasive devices exist which are used externally to measure either the concentration of the constituent in gases admitted by the body or the concentrations contained in a patient""s body part, typically a finger. U.S. Pat. No. 5,429,128 describes a finger receptor that receives a finger of a user and is for use with a non-invasive monitoring device, such as that described in U.S. Pat. No. 5,361,758.
During the course of using a monitoring device that is operatively coupled to a finger receptor, many uses of the receptor and the monitoring device will with time result in variations in reading due to internal drift and other variable aspects of such monitoring devices. Accordingly, it is desirable to have a means to rapidly and easily check the precision and accuracy of such a monitoring device.
The present inventors have developed a device shaped to fit a receptor that is operatively connected to a non-invasive monitoring device, which device is useful in monitoring the precision and accuracy of the non-invasive monitoring device and which permits photometric correction of the instrument.
In its broad aspect, the invention provides a method and a device made of materials for carrying out the method which reproduces absorption spectra associated with various body parts when such parts are subjected to spectral determination. A device according to the present invention is made of a material that exhibits the same light scattering and absorbency characteristics as a body part, preferably of an earlobe, lip, fold of skin or finger, most preferably, a finger.
According to one embodiment of the present invention there is provided an artificial member that mimics the absorbance spectrum of a body part and includes the spectral components of blood analytes comprising a light scattering and reflecting material, which member has a chamber portion comprising one or more chambers, the member configures to be reproducibly received in a measuring receptor that is operatively connected to a non-invasive monitoring device, preferably, the body part that is mimicked is a finger. In one embodiment, there is one chamber, while in another, there are two chambers.
In another embodiment, each chamber is filled with an O-cellulose material that mimics light scattering properties of tissue, preferably each chamber is filled with a gel material containing amaranth dye and sodium benzoate and holding light scattering and reflective particles that mimic the light scattering properties of tissue.
In another embodiment, the material that fills each chamber is fluid free. In yet another embodiment, the reflective particles comprise Teflon(copyright)-PTFE (polytetrafluoroethylene) (DuPont, Wilmington, Del., USA), titanium dioxide (TiO2) or are polystyrene nanospheres.
In yet another embodiment, the light scattering and reflecting material of the member is Teflon(copyright)-PTFE, preferably the configuration of the member wherein the configuration of the member to be reproducibly received, comprises a stabilizing member extending from the chamber portion to reversibly urge other surfaces of the member into contact with the measuring receptor, preferably the stabilizing member is as depicted in FIG. 9.
In another aspect according to the present invention, there is provided a method of transferring algorithms from one spectral instrument to another, the method involving: measuring a spectral response of a member in a first spectral instrument; measuring a spectral response of the member in a second spectral instrument; determining any difference in measurements between the first instrument and the second instrument; and modifying the algorithms of the instruments to account for any difference, wherein the member of the method mimics the absorbance spectrum of a body part and includes the spectral components of blood analytes comprising a light scattering and reflecting material, which member has a chamber portion comprising one or more chambers, the member configures to be reproducibly received in a measuring receptor, that is operatively connected to a non-invasive monioring device, preferably the body part mimicked is a finger. In one embodiment of the method, there is one chamber, while in another there are two chambers.
In another embodiment of the method, each chamber is filled with an O-cellulose material that mimics light scattering properties of tissue, preferably each chamber is filled with a gel material containing amaranth dye and sodium benzoate and holding light scattering and reflective particles that mimic the light scattering properties of tissue.
In another embodiment, the material that fills each chamber is fluid free. In yet another embodiment, the reflective particles comprise Teflon(copyright)-PTFE, TiO2 or are polystyrene nanospheres.
In yet another embodiment of the method. the light scattering and reflecting material of the member is Teflon(copyright)-PTFE, preferably the configuration of the member wherein the configuration of the member to be reproducibly received, comprises a stabilizing member extending from the chamber portion to reversibly urge other surfaces of the member into contact with the measuring receptor, preferably the stabilizing member is as depicted in FIG. 9.
The invention in another embodiment, provides a method for mimicking the absorbance spectrum of a body part that includes the spectral components of blood analytes, and comprises inserting a member in a measuring device operatively connected to a non-invasive monitoring device; taking measurements with the device and comparing the results with those obtained from a body part of a subject that the member is intended to mimic, wherein the member is comprised of a light scattering and reflecting material, which member is configured to be reproducibly received in the measuring receptor.
According to one embodiment of the method, the member mimics the absorbance spectrum of a body part and includes the spectral components of blood analytes comprising a light scattering and reflecting material, and the member has a chamber portion comprising one or more chambers, the member configured to be reproducibly received in a measuring receptor that is operatively connected to a non-invasive monitoring device, preferably the body part that is mimicked is a finger. In one embodiment of the method, there is one chamber, while in another there are two chambers.
In another embodiment of the method each chamber is filled with an O-cellulose material which mimics light scattering properties of tissue, preferably each chamber is filled with a gel material containing amaranth dye and sodium benzoate and holding light scattering and reflective particles which mimic the light scattering properties of tissue.
In another embodiment, the material that fills each chamber is fluid free. In yet another embodiment, the reflective particles comprise Teflon(copyright)-PTFE, TiO2 or are polystyrene nanospheres.
In yet another embodiment of the method, the light scattering and reflecting material of the member is Teflon(copyright)-PTFE, preferably the configuration of the member wherein the configuration of the member to be reproducibly received, comprises a stabilizing member extending from the chamber portion to reversibly urge other surfaces of the member into contact with the measuring receptor, preferably the stabilizing member is as depicted in FIG. 9.
In another aspect, the present invention provides an artificial member that mimics the absorbance spectrum of a body part and includes the spectral components of blood analytes, the artificial member comprising a container made of a light-scattering and reflecting material, the container comprising at least one chamber, the container having a neck extending from one end thereof, the neck comprising an orifice that is sealed with a cap, the member being configured to be reproducibly received in a measuring receptor that is operatively connected to a non-invasive monitoring device.
Preferably, the member further comprises a septum that fits over the orifice and is secured by the cap. In a preferred embodiment, the septum is uniform with the cap.
In another preferred embodiment, the neck comprises a flange, and the cap is secured over the flange. In another preferred embodiment, the flange is an annular flange.
In another preferred embodiment, the cap is a crimp cap, that is preferably made of aluminum.
In another preferred embodiment, the body part, which is mimicked is a finger.
In another embodiment, the member contains one chamber, while in another it contains two chambers. Preferably, the chamber is cylindrical.
In a further embodiment, each chamber is filled with an O-cellulose material that mimics light scattering properties of tissue. Preferably, each chamber is filled with a gel material containing amaranth dye and sodium benzoate and holding light scattering and reflective particles that mimic the light scattering properties of tissue.
In another embodiment, the material that fills each chamber is fluid free. In yet another embodiment, the reflective particles comprise Teflon(copyright)-PTFE, TiO2 or are polystyrene nanospheres.
In yet another embodiment, the light scattering and reflecting material of the member is Teflon(copyright)-PTFE, preferably the Teflon(copyright)-PTFE contains from about 0.1% to about 25% glass fiber. More preferably, the Teflon(copyright)-PTFE contains from about 0.1% to about 5% glass fiber.
In another preferred embodiment, the member comprises a stabilizing member extending from the chamber portion to reversibly urge other surfaces of the member into contact with the measuring receptor.
In a further aspect, the present invention provides a method for mimicking the absorbance spectrum of a body part that includes the spectral components of blood analytes, the method comprises:
(a) providing an artificial member comprising a container made of a light scattering and reflecting material, the container comprising one or more chambers, and having a neck extending from one end thereof, the neck comprising an orifice sealed with a cap, the artificial member being configured to be reproducibly received in a measuring receptor that is operatively connected to a non-invasive monitoring device;
(b) inserting the artificial member into the measuring receptor;
(c) taking measurements with the monitoring device; and
(d) comparing the measurements obtained in step (c) with those obtained from a body part of a subject, which the artificial member is configured to mimic.
Preferably, the artificial member used in the method further comprises a septum that fits over the orifice and is secured by the cap. In a preferred embodiment, the septum is uniform with the cap.
Other features and advantages of me present invention win become apparent from the following detailed description, drawings and claims. It should be understood, however, that the detailed description and the specific examples while indicating preferred embodiments of the invention are given by way of illustration only, and various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.